\section{Conclusion and Future Work} \label{sec:conclusion}
\vspace{-0.3cm} 
\noindent
%Bidirectional model transformations represent at the same time an intrinsically difficult problem and a crucial mechanism for keeping consistent and synchronized a number of related models. 
In this paper, we discussed the problem of non-determinism in bidirectional transformations.~In many respects, the multiplicity of solutions in non-bijective transformations is an aspect which has been largely neglected. Our proposal is based on JTL, a language which is able to generate more than one model at once, whose transformation engine has been revised to accommodate models with uncertainty. In particular, instead of a set of models the language is now able to generate a model with uncertainty which precisely denote the intended solution space. The technique required us to provide a metamodel-independent approach which can automatically derive an uncertainty metamodel from any MOF metamodel. Moreover, specific operators have been define to realize a complete interoperability between the base and the uncertainty metamodel in order not to invalidate existing tools. 

As future work, we plan to assist the modeler with proper visualization which is of great importance for enhancing the usability: it would be tremendously difficult to find a model satisfying a little property among dozens of models very similar each other. The modeler would greatly benefit from 
hiding, partitioning, constraining, and abstracting while traversing an uncertain model. Moreover, whenever certain uncertain aspects are resolved, the decision must be appropriately recorded and documented. 
\vspace{-0.4cm}
